Hydraulic chuck-operating mechanism



Nov. 10, 1 936. w, E s AL 2,060,293

HYDRAULIC CHUCK OPERATING MECHANISM Filed June 18, 1930 4 Sheets-Sheet lWALTER FERRIS. E FHBH ELWEILLAEGEH.

Nov. 10, 1936. w. FERRIS ET AL 2,060,293

HYDRAULIC CHUCK OPERATING MECHANISM Filed Jfine 18, 1950 4 Sheets-Sheet2 gwwntov WALTER F'E F F\ s. ERIEH E'IWEILLAEGER.

W. FERRIS AL HYDRAULIC CHUCK OPERATING MECHANISM Nov. 10, 1936.2,060,293

4 Sheets-Sheet 3 Filed June 18, 1930 H n nu \Mm d gww'ntcw WALT ERFERRIS.

' ERIDH E.WIH LAEE1'EH.

Noy. 10, 1936. w. FERRIS ET AL 2,060,293

I HYDRAULIC CHUCK OPERATING MECHANISM Filed June 18, 1950 4 Sheets-Sheet4 F g. 1D.

gwumtoz VVALT ER F'ER R13. EFilEH-l E.WEILL.AEI3ER.

Patented Nov. 10, 1936 UNITED STATES HYDRAULIC CHUCK OPERATING MECHANISMWalter Ferris, Milwaukee, Wis., and Erich C. Wollaeger, Cleveland, Ohio,assignors to The Oilgear Company, Milwaukee, Wis., a corporation ofWisconsin Application June 18, 1930, Serial No. 462,056

15 Claims.

This invention relates to chuck-operating mechanisms for multiplespindle machines.

The machine to which the invention is particularly adapted has a toolhead which carries 5 a number of tools, a spindle turret which carries anumber of rotary spindles having work-holding chucks upon the endsthereof, a chuck operating mechanism for opening and closing the chucks,and mechanism for rotating the spindle turret intermittently to bringthe chucks successively into registry with each of the tools.

The chuck-operating mechanism is ordinarily operated to open each chuckafter the same arrives at a certain station to allow the finished 15article held thereby to be removed and replaced by an unfinishedarticle.

The invention has as an object to provide a hydraulic chuck-operatingmechanism which is positive and precise in operation.

Another object is to open and close the chucks at high speed by means ofliquid supplied from one source and to hold the chucks closed by meansof liquid supplied from another source.

Another object is to provide means to open the chuck at one stationautomatically and to open a chuck at any station manually.

Another object is to provide a chuck-operating mechanism having a singlevalve which is capable of operating all of the chucks on the machine.

According to the invention, each chuck is operated by a piston and acylinder which are connected thereto, a relatively small volume ofliquid at a holding pressure is supplied to all of the cylinders to holdthe chucks closed, and a relatively large volume of liquid is suppliedto one cylinder at a time to open and close the chuck connected to thatcylinder without aflecting the holding pressure in the other cylinders.

' The invention further provides means for 40 opening the chuck at anystation and also a single valve for controlling the flow of liquid toall of the chuck cylinders.

A hydraulic chuck-operating mechanism embodying the invention isillustrated in the ac- 5' companying drawings in which the views are asfollows:

Fig. 1 is an elevation of a multiple spindle lathe to-which theinvention has been applied.

Fig. 2 is a cross-sectional view through the chuck-operating mechanism,taken substantially on the line 2-2 of Figs. 1 and 3.

Fig. 3 is in part a longitudinal section, taken on the broken line 3-3Fig. 2, and in part a schematic drawing showing a variable displacementpump and a gear pump connected to the chuck-operating mechanism forsupplying liquid thereto.

'Fig. 4 is a sectional plan through the main operating valve, taken onthe line 4-4 of Fig. 2 and showing the valve in position to open one 5o! the chucks.

Fig. 5 is a view similar to Fig. 4 but showing the valve in position tohold all 01. the chucks closed. v

Fig. 6 is a transverse'section through the valve, taken on a line 6-6Fig. 4.

Fig. 7 is a transverse section through the valve, taken on a line 1-1 ofFig.4.

Fig. 8 is 'an end view or the valve shifter, as indicated by line 8-8 0!Fig. 3.

Fig. 9 is a side view of the valve shifter, taken on the line 9-9 ofFig. 8.

Fig. 10 is a schematic drawing showing an 'arrangement wherein thechucks are opened and closed by liquid supplied from a pump and heldclosed by liquid supplied from an accumulator.

Fig. 11 is a schematic drawing showing an ar-- rangement wherein thechucks are opened and closed by liquid supplied from an accumulator andheld closed by liquid supplied from a pump.

The invention is shown applied to a multiple spindle lathe, such as theCleveland five-spindle chucking lathe shown in the catalog of theCleveland Automatic Machine Company of Cleveland, Ohio, but theinvention is not limited to this particular application.

This machine has a bed I, a tool head 2 arranged thereon and providedwith five tools 3, a-spindle turret 4 arranged upon the bed I andprovided with five spindles 5 having chucks 6 35 upon the outer endsthereof to hold the articles to' be machined, a chuck operating unit 1arranged upon the bed I to open and close the chucks 6, and a cam drum 8which controls the chuck-operating unit.

The spindles I arerotated continuously upon their individual axes andintermittently revolved about a common central axis from one station toanother which correspond to the stations of the tools I, and the camdrum 8 is rotated continuously in synchronism with the mechanism whichintermittently revolves the spindles 5 from station to station. I

Each chuck 6 rotates the article c'arried thereby and the tool head 2 isadvanced to bring the tools 3 into engagement with the articles carriedby the corresponding chucks to machine the same. The five articles arethus machined simultaneously but each tool ordinarily performs a.diiierent operation. 56

I ticle.

When the operations at all stations are completed, the spindles 5 arerevolved to move the article carried by each chuck 6 to the next stationwhere it is operated upon by the tool at that station.

After each chuck arrives at a certain station,

which is generally termed the loading satlon, thedrum 8 actuates thechuck-operating unit to open that chuck and allow the article carriedthereby to be removed and replaced by an unfinished ar- The cam 8 thenactuates the chuck-operating unit to close the chuck and secure theunfinished article therein.

The tool at the loading station has a shorter operation to perform thanthe other tools, in order to allow time for changing the article held bythe chuck at that station, and this operation may be either the first orthe last operation performed upon an article by the machine. If theformer, each chuck is opened as soon as it arrives at the loadingstation and, if the latter, the chuck at the loading station is openedas soon as the tool completes its operation.

The machine thus far described is a standard machine having either amechanical or a pneumatic chuck-operating unit and forms no part of thepresent invention which is directed to hydraulic mechanism for operatingthe chucks.

Figs. 1 to 9 The chuck-operating mechanism is arranged within a housing9 which is carried by the bed I and closed at its rear end by astationary bearing plate I. The front end of the housing 9 is closed bya circular head II which is rotatable therein and held against axialmovement by a ring l2 secured to the housing 9.

The cylinder l 3 of an operating or control valve l4 has its rear endjournaled in the bearing plate It and its forward end attached to therear end of a support l5 which is coaxial with the head i l and fixedthereto to rotate the cylinder l3 in unison therewith.

The support l5 also has a circular supporting plate l6 fixed to the rearend thereof which carries five hub bearings I! in each of which the huhI 8 of a cylinder I9 is journaled. Each cylinder I9 is closed at itsrear end by the hub i8 and at its forward end by a cylinder head 29which has a spindle 2| formed integral therewith and journaled in thehead I I. The head I I, valve cylinder [3 and cylinders 20 are thusformed into a complete rotatable unit which has its rear end journaledin the bearing plate l and its forward end journaled in the front end ofthe housing 9.

Each spindle 2| is attached to one of the spindles and the chuck 6carried thereby is operated by a piston 22 which is arranged in thecylinder l9 and has its rod 23 connected to the operating rod 24 of thechuck 6. The operating rod 24 and the connection for attaching thespindle 2| to the chuck spindle 5 are parts of the spindle turret 4 andform no part of the present invention.

The pistons 22 are reciprocated to operate the chucks 6 by liquidsupplied to the cylinders l9 under pressure, and leakage of liquid fromthe cylinders I9 is prevented by packing 25 which is arranged in thespindles 2i and encircles the piston rods 23.

The spindles 2| and the cylinders l9 are rotated by the chuck spindles 5and the pistons 22 are rotated in unison therewith by the chuckoperatingrods 24; the valve spindles 2| rotating in the head H and the hub I8 ofthe cylinders l9 rotating in the hub bearings I! which are secured inthe supporting plate I6 by keys 26.

The pistons 22 are moved to open and close the chucks 6 by a liquid,such as oil, under a comparatively low pressure and are acted upon byliquid under a comparatively high pressure to hold the chucks 6 closed.

The low pressure liquid may be supplied by a gear pump 21 and the highpressure liquid by a variable displacement pump 28 which has thecharacteristic of delivering the volume of oil required to maintain anypredetermined pressure within the capacity of the pump. The pump 28 maybe of the type disclosed in Patent No. 1,578,233, issued to WalterFerris March 23, 1926, and the gear pump 21 may be incorporated thereinas disclosed in Patent No. 1,619,200, issued to Walter Ferris March 1,1927, or the gear pump '21 may be driven in conjunction with pump 28 andconnected to the sump thereof as indicated diagrammatically in Fig. 3.

Liquid from the pumps 21 and 28 is delivered to the operating valve l4through a delivery ring 29 which is journaled upon the valve cylinder l3and held against rotation by a bolt 39 carried by the bearing plate I0.The ring 29 is provided upon its inner periphery with three annulargrooves 3|, 32 and 33 which register, respectively, with ports 34, 35,and 36 formed in the side walls of the cylinder IS.

The pump 28 delivers high pressure liquid to the valve cylinder l3through a pipe 31, a threeway valve 38 and a pipe 39, the upper end ofwhich is connected tothe delivery ring 29 and communicates with thegroove 3| and the port 34. The valve 38 is also connected to the intakeof the pump 28 by a pipe 49 and may be operated to stop the delivery ofliquid to the valve cylinder l3 and return the same directly to thepump.

The gear pump 21 delivers low pressure liquid to the valve cylinder I3through a pipe 4| which is provided with a check valve 42 to protect thepump 21 from high pressure. The pipe 4! is connected at its upper end tothe delivery ring 29 and communicates with the interior of the valvecylinder l3 through the groove 32 and the port 35.

Liquid in the rear end of the cylinder 1 3 may drain into the housing 9through the ports 38, the groove 33 and a drain opening 43 which extendsthrough thedelivery ring 29 and registers with the groove 33. Liquid inthe front end of the cylinder l3 may drain into the housing 9 throughdrain openings 44, which are formed in the side wall of the cylinder l3,and the liquid collected in the bottom of. the housing 9 may drain intothe sump of the pump 28 through a drain pipe 45. r

The hub bearing ll of each clutch cylinder I9 is connected to the valvecylinder l3 by a pipe 46, which has one end in communication with a port41 in the wall of the cylinder l3 and its other end in communicationwith an annular groove 48 formed upon the periphery of the cylinder hubl8, and by a pipe 49 which has one end in communication with a port 59in the wall of the cylinder l3 and its other end in communication withan annular groove 5| formed in the cylinder hub l8.

Low pressure liquid delivered through the pipe 46 to the groove 48 isconducted into the rear end of the cylinder l9 through a duct 52 toadvance the piston 22 and open the clutch 6, and low pressure liquiddelivered through the pipe 49 to the groove 5| is conducted into thefront end of the cylinder l8 through a duct 83 to retract the piston 22and close the chuck 8.

The groove 5| is also connected to the cylinder i3 through a choke coil54which is connected between the pipe 49 and a port 55 in the wall ofthe cylinder 3. High pressure liquid delivered through the port 55'andthe choke coil 34 increases the pressure in the cylinder l9 and causesan article to be firmly gripped by the jaws of the chuck 8 after thesame have been closed by the low pressure liquid delivered through thepipe 49.

The liquid delivered to the chuck cylinders l3 and the liquid dischargedtherefrom flows through ducts formed in the valve H which controls theoperation of the chuck pistons 22. When'the valve I4 is advanced asshown in Figs. 3 and 5, all of the pistons 22 are retracted and all ofthe chucks 6 are held closed and, when the'valve i4 is retractedas shownin Fig. 4, one chuck only is open and the other chucks are held closed.

The chuck at any station may be opened manually by operating the valve Hwhich is ordinarily adjusted to automatically open each chuck as thesame arrives at a certain station. As shown, the valve is adjusted toopen the chuck at station A.

The ports 34 are always in registry with an annular groove 58 which isformed in the periphery of the valve l4 and connected by a duct 51 to anannular peripheral groove 58 which is always in registry with the ports55 so that high pressureliquid may be delivered to all of. the cylindersI! at all times.-

The ports 35 are always in registry with an annular groove 58 which isformed in the periphery of the valve I4 and connected by a duct 80 to arecess 6| which is formed in the periphery of the valve H in radialalignment with station A and opens into anannular groove 62.

When the valve I4 is advanced and all of the chucks 8 are closed, thegroove 62 is in registry with all of the ports 50 and, when the valve I4is retracted, the groove 82 moves out of registry with the ports 58 andthe recess 6| moves into registry with the port 41 at station A, so thatliquid may be delivered by the gear pump 21 to the rear end of thecylinder I! atthat station to open the chuck 6.

Theports 41 are normally in registry with an annular groove 63 fromwhich a discharge duct 84 leads through the body of the valve 4 andopens into the cylinder |3 at the forward end thereof. The drain groove64 also has an inlet 88 which is arranged in radial alignment withstation A and is normally out of registry with any port, but itregisters with the port 58 at station A when theyalve i4 is retracted sothat liquid may be discharged from the'front end of the cylinder |9atthat station.

The valve I4 is moved axially by its stem 66 which extends through" thehead 81 of the cylinder l3 and has the outer part thereof reduced indiameter to provide a'shoulder 88. A thrust Y collar "is Journaled uponthe reduced part of the stem -i6 and held against axial movement-relatively thereto by the shoulder 88 and an a bracket I4 carried bythe housing 3. The lever 13 holds the thrust collar 83 against rotationand the valve I4 is held against'rotation by a pin 15 which is carriedby the index plate Ill and adapted to be inserted in any one of fiveholes 5 16 which are formed in the thrust collar 68 and correspond tothe normal positions of the five chucks. I The lever 13 is actuated by alever 'i'l which has one end fixed upon a shaft .18 carried by the bed Iand its otherend bifurcated and engaging 'a pin 19 carried by the lowerend of the lever I3.

The lever 11 may be actuated by a hand lever 80, which is fixed to theshaft 18, or by a cam lever 8| which is journaled upon the shaft 18 andprovided at its lower end with a roller 82 which rides in the cam groove83 of the drum 8. The cam lever 8| actuates the lever 11 through an arm84 which is fixed to the lever 8| and provided with a notch 85 normallyengaged by a latch 88' carried by the hand lever 80.

When the roller 82 is moved toward therear of the machine by the camgroove 83, the cam lever 8| will rock the shaft 18 -and swing the lever11 to actuate the operating lever 13 and cause the same to retract thevalve H.

The gear pump 21 will then deliver liquid under pressure to the cylinderIs at station A through the pipe 4|, check valve 42, delivery ring 29,port 35, groove 58, duct 88 and recess 8| to the port 41 at station Aand thence through the pipe 46, groove 48, and duct 52 to the'rear endof the cylinder l9 to force the piston 22 outwardly and open the chuck 6at that station.

As the piston 22 moves forwardly, the liquid in the forward end of thecylinder I9 is. expelled through the duct 53, groove 5|, pipe 48, port58, inlet 65 and drain duct 64 into the front end of the cylinder |3from which it drains through the drain openings 44 into the base of thehousing 9 and is returned to the sump of the pump 28 through the drainpipe 45.

The rear ends of all of the other cylinders l3 are open to the drain asthe groove 63 is of sufthe one at station A. The discharge of liquidthrough the choke coil 54 at station A is so small that it does notaffect the operation of the piston 22 at that station nor lower theholding pressure in the cylinders at the other stations.

The cam drum 8 is rotating continuously and the cam groove 83 is soarranged as to allow sufficient time to remove the finished article fromthe chuck at station A and replace the same with an unfinished article.

The cam lever 8| is then moved in the opposite direction by the camgroove 83 to advance the valve I4 and thereby move the inlet 85 out ofregistry with the port 50 at station A and the groove 62 into registrytherewith and the recess 8| out of registry with the port 41 at stationA and the groove 83 into-registry therewith.

Low pressure liquid will now flow through the groove 82, port 58, pipe48, groove 5|, and duct 83 to the front end of the cylinder l9 andretract the piston 22 to close the chuck and secure the i work therein.After the piston 22 has been re- 75 tracted by the low pressure liquid,the high pressure liquid delivered through the choke coil 54 will buildup the pressure in the forward end of the cylinder l9 and cause thepiston 22 to be forced rea'rwardly under high pressure and firmly gripthe article in the chuck 8. The article is then in condition to be actedupon by the tool 3.

When the piston 22 at station A is retracted, the liquid in the rear endof the cylinder I9 is expelled through the duct 52, groove 48, pipe 46,port 41, groove 83, duct 84 and into the front end of the cylinder Hfrom which it is discharged through the drain 44.

In case it is desired to open the chuck at any of the other stations,the pin 15 is removed and the valve I4 rotated by means of the handleuntil the pin 15 can be inserted in the hole 18 corresponding to thatstation.

The recess GI and the inlet 85 will then register, respectively, withthe port 41 and the port 50 at that station when the valve I4 isretracted. Consequently, the chucks will open and close after the samearrive at this station and remain closed at all of the other stations.

It it is desired to remove or adjust the article at any station otherthan the loading station, the valve 4 is rotated as described above, thelatch 88 is withdrawn from the notch 85, and the hand lever 88 isoperated to actuate the lever 13 and retract the valve l4.

The recess BI and the inlet 85 are thus moved, respectively, intoregistry with the port 41 and the port 58 at that station, and thepiston 22 is retracted to open the chuck. After the article has beenremoved or adjusted, the hand lever 88 may be operated to advance thevalve 4 and close the chuck.

Figs. 10 and 11 The arrangements shown in these fig es differ from thearrangement shown in Figs. 1 to 9 only in employing a pump and anaccumulator instead of two pumps as the two sources of pressure, andlike parts have been indicated by like reference characters.

In the arrangement shown in Fig. 10, the chucks are opened and closed byliquid supplied from a high pressure pump 28A and are held closed byliquid supplied from an accumulator 81.

The valve 38 may be employed to direct the output of the pump 28-A intothe return pipe 40 when the machine is idling, as previously described,and the pump 28-A may be either a variable delivery pump or a constantdelivery pump. If a constant delivery pump is employed, excess liquid isreturned to the pump through a high pressure relief valve 88 which isconnected between the delivery pipe 31 and the return pipe 45 andadjusted to open at a predetermined pressure.

The chucks are held closed by liquid supplied through the pipe 39 andthe chuck at the loading station is opened and closed by liquid suppliedthrough the pipe 4|, as previously described.

The pipe 4| is connected to the valve 38 and the entire output of thepump 28A is available for opening and closing the chuck at the loadingstation.

The pipe 39 is connected to the accumulator 81 and also to a check valve89 which is connected to the pipe by a pipe 90. Liquid delivered by thepump 28--A thus passes into the pipes 39 and 4| to hold the chucksclosed and to charge the accumulator 81 to a predetermined pressure.

When the valve i4 is operated to open and close the chuck at the loadingstation, the pressure in the pipe 4| drops momentarily, due to thesudden demand iipon the pump 28A for an increased volume of liquid, andthe check valve 89 closes to prevent the pressure in the pipe 39 fromdropping. The accumulator 81 maintains the pressure in the pipe 39 andin the chuck cylinders at the other stations.

After the chuck at the loading station has been closed, the pressure inthe pipe 4| increases to the predetermined maximum and the accumulator81 is recharged.

The pump 28-A thus supplies liquid at a predetermined pressure to holdallof the chucks closed and the relatively large volume required to openand close one chuck at high speed, and the accumulator supplies arelatively small volume of liquid at the predetermined pressure to holdthe four chucks closed when one chuck is open.

In the arrangement shown in Fig. 11, the chucks are held closed byliquid supplied through the pipe 39 from the pump 28-A and the chuck atthe loading station is opened and closed by liquid supplied through thepipe 4| from an accumulator 9|.

The pipe 38 is connected directly to the valve 38 and the pipe 4| isconnected to the accumulator 9| and is also connected to the valve 38through a high pressure resistance valve 92 which is adjusted to open ata pressure slightly lower than the pressure at which the relief valve 88opens.

When the valve i4 is operated to open and close the chuck at the loadingstation, liquid is delivered from the accumulator 9| to the chuckcylinder at that station and the pump 28-A maintains a constant pressurein the chuck cylinders at the other stations equal to the pressurerequired to open the resistance valve 92.

Only a small part of the output of the pump 28--A is required tomaintain this holding pressure and the balance of the output passesthrough the resistance valve 92 to assist the liquid supplied from theaccumulator 9| in opening and closing :the chucks at the loadingstation. Thus a small accumulator will suffice.

When the chuck at the loading station has been closed, the pump 28Arecharges the accumulator 9| which is then in condition to open andclose the next chuck when the same arrives at the loading station.

The invention herein set faith is susceptible of various modificationsand adaptations without departing from the scope thereof as hereafterclaimed.

The invention is hereby claimed as follows:

1. The combination, with a machine having a number of work-holdingchucks movable from station to station, of a hydraulic chuck-operatingmechanism comprising a cylinder and a piston connected to each of saidchucks for operating the same, means for supplying liquid continuouslyin limited volume and at a holding pressure to each of said-cylinders tohold said chucks closed, and means for supplying liquid in larger volumeto the cylinder at one of said stations to open and close the chuck atthat station without interrupting the delivery of said limited volume ofliquid or affecting the holding pressure in the cylinders at the otherstations.

2. The combination, with a source of fluid under pressure and a machinehaving a number of chucks revoluble about a common axis and operated bypistons arranged in cylinders connected to said chucks, of means foropening a d 1 'tion to direct fluid from said source to one ing saidchucks comprising a valve cylinder rotatable in synchronism with saidchuck cylinders and having an inlet connected to said source and fluidfrom said source to said chuck cylinders and thereby control themovement of said pistons to open andclose said chucks.

3. The combination, with a source of fluid under pressure and a machinehaving a number of chucks intermittently revoluble from station tostation about a common axis and operated by pistons arranged incylinders connected to said chucks 01 means for opening and closing saidchucks comprising a valve cylinder rotatable in synchronism with saidchuck cylinders and having an inlet connected to said source and outletconnected to said chuck cylinders, a normally nonrotatable valvearranged in said valve cylinder to control said inlet and said outletsand having passageways to connect said inlet to said outlet and a drainfor the passage of fluid discharged from said chuck cylinders, and meansfor moving said valve to one position to direct fluid from said sourceto one end of each of said chuck cylinders and hold said chucks closedand for moving said valve to a second position to direct fluid to theother end of the chuck cylinder at one of said stations to open thechuck at that station.

4. The combination, with a source of fluid under pressure and a machinehaving a number of chucks intermittently revoluble from station tostation about a common axis and operated by pistons arranged incylinders connected to said chucks, of means for opening and closingsaid chucks comprising a valve cylinder rotatable in synchronism withsaid chuck cylinders and having an inlet connected to said source andoutlets connected to said chuck cylinders, a normally nonrotatable valvearranged in said valve cylinder to control said inlet ,and said outletsand having passageways to connect said inlet to said outlets and a drainfor the passage of fluid discharged from said chuck cylinders, automaticmeans for moving said valve axially to one position to direct fluid fromsaid source to one end of each of said chuck cylinders and hold saidchucks closed and for moving said valve to a second position to directfluid to the other end of the chuck cylinder at one of said stations toopen the chuck at that station, and manual means for rotating said valveto change the station at which the chuck will be opened upon theautomatic operation of said valve.

5. The combination, with a source of fluid under pressure and a machinehaving a number of chucks intermittently revoluble from station tostation about a. common axis and operated by pistons arranged incylinders connected to said chucks, of means for opening and closingsaid chucks comprising a valve cylinder rotatable in synchronism withsaid chuck cylinders and havend of each of said chuck cylinders and holdsaid chucks closed and for moving said valve to a second position todirect fluid to the other end oi the chuck cylinder atone oi! saidstations to open the chuck at that station, manually operable means forrotating said valve to a new position, and manually operable means formoving said valve axially to open and close a chuck at a differentstation.

6. The combination, with a source of liquid under pressure and a machinehaving a number of spindles intermittently revoluble from station tostation about a common axis and provided with work-holding chucks, of ahydraulic chuck operating mechanism comprising a cylinder carried byeach of said spindles, pistons arranged in said cylinders and connectedto said chucks for open- 1 ing and closing the same, means fordelivering liquid to the cylinder at a predetermined. station to openand close the chuck at that station, and means for supplying liquid toall of said cylinders to hold the chucks at all other stations closedincluding a choke connected to the cylinders at said predeterminedstation to limit the flow of liquid through said supplying means to saidcylinder whereby a holding pressure is maintained in all othercylinders.

7. The combination, with a source of liquid under pressure and a machinehaving a number of spindles intermittently revoluble from station tostation about a common axis and provided with work-holding chucks, of.ahydraulic chuckoperating mechanism comprising acylinder carried by eachof said spindles, pistons arranged in said cylinders and connected tosaid chucks for opening and closing the same means for connecting oneend of each of said cylinder to said source to supply liquid thereto forholding said chucks closed, means for releasing the pressure in thecylinder at one of said stations, means for connecting the other end ofthat cylinder to said source to supply liquid thereto for opening thechuck at that station, and means for selecting the station at which achuck may be opened.

8. The combination, with two sources of liquid under pressure and amachine having a number of spindles intermittently revoluble fromstation to station about a common axis and provided with work-holdingchucks, of a hydraulic chuck-operating mechanism comprising a cylindercarried by each of said spindles, pistons arranged in said cylinders andconnected to said chucks for opening and closing the same, a valvecylinder revoluble in synchronism with said chuck cylinders and havinginlets connected to both of saidsources and outlets connected to saidchuck cylinders, a normally non-rotatable valve arranged in said valvecylinder to control said inlets and outlets and having passageways toconnect said inlets to said outlets and a drain for the passage ofliquid discharged from said chuck cylinders, and means for moving saidvalve axially to one position to direct the liquid from both of saidsources to the closing end of said chuck cylinders to close said chucksand for moving said valve to a second position to direct fluid from oneof said sources into the releasing end of the chuck cylinder at one ofsaid stations to open the chuck at that station and to maintain theother cylinders in communication with the other source of liquid to holdthe other chucks closed.

9. The combination, with two sources of liquid under pressure and amachine having a number of spindles intermittently revoluble fromstation to station about a common axis and provided with work-holdingchucks, of a hydraulic chuck-operating mechanism comprising a cylindercarried by each of said spindles, pistons arranged in said cylinders andconnected to said chucks for opening and closing the same, a valvecylinder revoluble in synchronism with said chuck cylinders and havinginlets connected to both of said sources and outlets connected to saidchuck cylinders, a. normally non-rotatable valve arranged in said valvecylinder to control said inlets and said outlets and having passagewaysto connect said inlets to said outlets and a drain for the passage ofliquid discharged from said chuck cylinders, automatic means for movingsaid valve axially to one position to direct the liquid from both 01'said sources to the closing end of said chuck cylinders to close saidchucks and for moving said valve to a second position to direct fluidfrom one of said sources into the releasing end of the chuck cylinder atone of said stations to open the chuck at that station and to maintainthe other cylin-' ders in communication with the other source of liquidto hold the other chucks closed, and manually operated means Iorrotating said valve to change the station at which a chuck will beopened upon the automatic operation of said valve.

10. The combination, with two sources of liquid v under pressure and amachine having a number of spindles intermittently revoluble fromstation to station about a common axis and provided with work-holdingchucks, of a hydraulic chuckoperating mechanism comprising a cylindercarried by each of said spindles, pistons arranged in said cylinders andconnected to said chucks for opening and closing the same, a valvecylinder revoluble in synchronism with said chuck cylinders and havinginlets connected to both of said sources and outlets connected to saidchuck cylinders, a normally non-rotatable valve arranged in said valvecylinder to control said inlets and said outlets and having passagewaysto connect said inlets to said outlets and a drain for the passage ofliquid discharged from said chuck cylinders, automatic means for movingsaid valve axially to one position to direct the liquid from both ofsaid sources to the closing end of said chuck cylinders to close saidchucks and for moving said valve to a-second position to-direct fluidfrom one of said sources into the releasing end of the chuck cylinder atone of said stations to open the chuck at that station and to maintainthe other cylinders in communication with the other source of liquid tohold the other chucks closed, manually operatable means for rotatingsaid valve to a new position, and manually operatable means for movingsaid valve axially to open and close the chucks.

11. The combination, with a source of liquid under pressure and achucking mechanism having a rotary work-holding chuck, of a bearinghaving ducts connected to said source, a cylinder connected to saidchuck to rotate therewith and iournaled in said bearing and having ductscommunicating with the ducts in said bearing to deliver liquid from saidsource to the interior of said cylinder, a piston arranged in saidcylinder and actuated by liquid to operate said chuck, and a housingarranged around said cylinder and connected to said source to collectliquid escaping from said ducts and said cylinder and return the same tosaid source.

12. The combination, with a source oi. liquid under pressure and achucking mechanism having a rotary work-holding chuck, of a cylinderconnected to said chuck to rotate therewith, a piston arranged withinsaid cylinder and connected to said chuck to operate the same, a hubcarried by said cylinder and having ducts communicating with theinterior thereof, a bearing surrounding said hub and having ductscommunicating with the ducts in said hub and connected to said source todirect liquid into said cylinder to actuate said piston, and a housingarranged around said cylinder, and connected to said source to collectliquid escaping from said ducts and said cylinder and return same tosaid source.

13. The combination, with a machine having a number of cylinders and apiston arranged in each cylinder, of means for supplying relativelylarge volumes of liquid to said cylinders selectively to operate saidpistons individually, means for supplying relatively small volumes ofliquid at a holding pressure to all of said cylinders to hold saidpistons in operated positions after the same have been operated by saidlarge volume means, and a choke connected to each cylinder and in cludedin said small volume means to limit the volume of liquid deliveredtherethrough to each of said cylinders to thereby allow one or saidpistons to be operated by liquid delivered through said large volumemeans without afiecting the holding pressure in any other cylinder.

14. The combination, with a source having a limited capacity forsupplying liquid under pressure and a chucking mechanism having a numberof independently rotatable chucks, or a cylinder and a piston connectedto each of said chucks and rotatable therewith, and means including achoke coil for delivering liquid from said source to said cylinders foractuating said pistons to operate said chucks.

15. The combination, with two sources of liquid under pressure and achucking mechanism having a number of independently rotatable chucksrevoluble about a common axis, of a cylinder and a piston 'connected toeach of said chucks and rotatable therewith, a valve connected to bothof said sources to control the flow of liquid from said sources to saidcylinders, means connecting said cylinders to said valve to directliquid from one 01' said sources to said cylinders for operating saidchucks, and means including choke coils for connecting each of saidcylinders to said valve to direct liquid from the other of said sourcesto said cylinders tor holding said chucks closed.

ERICH C. WOILAEGER. WALTER FERRIS.

